As we come on the air, a giant witch's brew of weather is marching across the country, arctic air, snow, ice, even the threat of tornadoes. Tonight, 30 million people, 19 states from arizona to illinois are in the storm zone, under watches and warnings. And here are some pictures that tell the story. Out in california, a school bus sliding off a snow-covered highway. And in arizona, a cactus is frosty white. Abc's weather editor sam champion has tracked it all. Reporter: It started as a brutal wintry blast covering california with wind, rain and snow. Drivers unprepared for the messy conditions slipped, skidded and spun out, causing pileups. It's terrible, because they can't clean the roads. And it will just get worse. Reporter: And stranding hundreds of drivers, some for hours after icy highways were shut down. I was going to sonora. I know, but it's not the road, it's too icy. We keep having people spin off the roads. School bus to slide off the Reporter: Ice caused this school bus to slide off the road, injuring four students and the bus driver. Also reported, two tornadoes, one confirmed touchdown in gerber, california, tearing off the roof of a barn. And now the storm moves east. Officials already helping distressed drivers on snow-covered roads in kansas. In arizona today, the pga suspended its champion because of snow-covered greens. At tulsa international airport, workers raced to clear off planes through nearly whiteout conditions. Snowfall will stretch from denver, where up to six inches is expected wednesday, and head east, with up to a foot or more expected west of kansas city by late thursday. Now the nation's heartland preparing for what could be the worst storm to hit the midwest since the groundhog day blizzard in 2011. The snow may not be the only problem, and diane, it may not be the biggest problem. Look at this storm system, when it finally gets together. You are not seven eaching the real storm. The storm really kicks in tomorrow, getting all its energy. It has a layer of ice and that's basically, already ice storm warnings out for northern arkansas and southern missouri. That's miserable ice, we think. And this line of severe storms from new orleans, including texas, all the way to mississippi. Those storms could have or the nay domes in them. We could be reporting on all of it during the day tomorrow. Just something everyone should A lot of everything. Reporter: A lot. Heading their wa thank you so much, sam. Good to see you tonight.

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